Solutions for identification on the basis of RFID technology are applied in increasing lines of business. This may require the development of entirely novel types of RFID tags or the improvement of tag types already known, to find solutions which are as functional and inexpensive as possible but also affect the conventional use of the object as little as possible. In some applications, it may be difficult to read RFID tags attached in conventional ways, for example in the form of labels, to the object to be identified, because the tag cannot be easily attached to a place where it can be read electronically without obstacles. For example, in case of several products which should be identified separately from each other and which are stacked next to and/or on top of each other, the RFID tags of the sticker or label type require that these products are unpacked from their packaging so that the tags can be fixed to a place that is technically suitable for reading. Such products include, among other things, bottles or cans which are packed in the same packaging and whose use or consumption is to be controlled by identification based on RFID technology. Particularly in liquid packaging, the functionality of the RFID tag is significantly influenced by the location where the tag is fixed in the package, because the vicinity of liquids as well as metals will have a degrading effect on the readability of the RDIF tag.
Document WO 2007/042879 discloses a solution for a situation of the above-described kind, in which gas bottles are identified by using an RFID tag to be mounted onto the neck of the gas bottle. In this solution, the body of the RFID tag is provided with a receptacle in which the part that comprises the transponder (that is, the RFID chip and antenna) of the RFID tag is fixed by means of a relatively tight fit and a form joint between this part and the edges of the receptacle. For attaching the RFID tag onto the neck of the gas bottle, the edge of the body is provided with a collar that can be closed and opened, which is closed and locked around the neck of the gas bottle when the RFID tag is attached to the bottle. The sealability is implemented by making the collar of two parts, of which the first one is integrated in the body and the second one is a separate collar part which is connected to this by hinges and which can be switched open and closed and locked to the first part in such a way that these parts make up a closed annular loop connected to the body of the RFID tag. The aim of such a body structure and the attachment provided by it has been, among other things, to improve and to facilitate the usability of the RFID tag as well as to reduce interference on the RF signal possibly caused by the gas bottle made of metal, in comparison with a tag of the label type. However, the RFID tag implemented in this way has the disadvantage of a relatively complex structure, which makes it a relatively expensive solution with respect to, for example, RFID tags of the label type. In particular, if the products to be provided with such an RFID tag are products having a clearly lower price value than gas bottles, such an RFID tag body composed of several different parts is too expensive a solution for attaching the RFID tag. In many applications, the lock-up attachment of the RFID tag to the object does not have a significant value as such. Particularly in the marking of products with a low price, the utility value of the RFID tag is not diminished even if the tag could be detached from the object relatively easily.
Document WO 01/43096 discloses a system, a method, and an apparatus for controlling the consumption and sales of soft drinks in restaurants and bars. Here, sensors are provided on bottles used for storing beverages, on taps for beverages to be dispensed from a container, at doors of refrigerating rooms used for storing beverages, etc. to identify the object of use and to determine/evaluate the consumption of the beverage in question and to send this information to a computer controlling the system. In this case, a sensor attached to a single bottle may be attached, for example, to the bottom or the neck of the bottle. The sensor to be attached to the neck of the bottle is made annular so that it can be fitted around the neck of the bottle. The sensor always comprises a housing composed of separate parts, as well as, among other things, a separate power source and a radio transmitter which takes care of the data transmission between the sensor and the computer that controls the system; in other words, the sensors are so-called semi-active identifiers in the sense of identification. Because of their functions and structure, the sensors to be attached to a bottle, as presented in this document, are clearly too complex and expensive in their structure for mere identification, and there are not at all suitable for the identification of products sold at a low price in, for example, wholesale or retail trade.